(1) Field of the Invention
The present invention relates generally to tillage equipment and more specifically to a dual function tillage and incorporation implement and an incorporator wheel support arrangement therefor.
(2) Related Art
Various combinations of cultivators, disks or chisel plows with a finishing or incorporating tool such as a harrow or rolling basket are available for preparing a seed bed for planting and incorporating chemicals into the soil. Although such implements are widely used in farming, many have one or more disadvantages such as a less than desirable chemical incorporation characteristic which can result in chemical streaking or banding or require a second pass through the field with the implement. Most incorporating implements are not sufficiently aggressive to bring up buried trash and increase ground cover for conservation tillage practices.
When a disk type of implement is used for incorporating, recommended procedures often include setting disk depth to twice the desired depth that incorporation is to take place, which results in heavy draft loads and increased chemical requirements. For example, if good incorporating to a two inch depth is required, the disk is typically set to a four inch depth, and chemical streaking is common at lower depths between two and four inches. Because some of the chemical gets below the desired level, the rate of application of the chemical has to be increased over what otherwise would be necessary if incorporation occurred only to the desired depth.
Spray nozzles are conventionally positioned near the front of the implement so that the chemical is mixed and spread by the tools. However, the spreading action of sweeps or similar tools can actually increases problems of banding and uneven chemical coverage as the tools bulldoze through the soil leaving a path with no chemical. In addition, the soil often is rough and includes ridges and the like so that the surface being sprayed is relatively uneven resulting in uneven spray patterns.
Bulldozing and streaking problems increase as the speed of the implement is increased thereby limiting the productivity of the implement. For example, the maximum speed of a disk or field cultivator, if not already limited by the extra draft of the deep penetration necessary for good incorporation to the desired level, is usually limited to six or seven miles per hour. An ideal range of incorporating speeds, however, includes an upper speed of around nine miles per hour.
Implements which include conventional field cultivator, chisel plow or disk sections often plug easily in wet and/or trashy conditions. Some dual function implements are relatively large and bulky and are difficult to transport and require lift assist wheels or other special lift structure to raise the trailing implements for transport. When the trailing implements are supported to facilitate vertical rocking in the ground-working position, instability during transport can be a problem. Wide gangs of incorporating or tillage tools on some implements reduce the number of possible implement width combinations that can be fabricated without nonconventional gang widths, thereby adding to manufacturing costs for implements with certain preselected widths.
Machines which use spider wheels mounted in gangs have trouble mixing soil and material to be incorporated since the wheels are typically arranged in gangs of six or more wheels and are supported by the top of ridges so the wheels do not mix the soil and material in the bottom of the valleys. Usually there is only one rank of wheels, and the wheels cannot be spaced close enough to each other for proper mixing action. The nonuniform soil flow created from the end of one gang of wheels to the beginning of the next causes an uneven soil surface profile, and the wheels leave furrows at the machine edges. The wheels also are not very aggressive and do not move much soil or lift much buried trash for conservation tillage.
Implements such as shown in U.S. Pat. No. 4,646,850 have been proposed which utilize rows of large diameter spider wheels, such as shown in U.S. Pat. No. 4,817,732, rotated in the soil about axes offset from the transverse direction to provide good incorporation and a smooth seed bed on previously tilled soil. Although providing good results, use of these implements usually requires a prior pass of a tillage implement such as a field cultivator or chisel plow to loosen the soil, cut the roots of existing plant growth and level the soil. Supporting the large wheels at an angle from the fore-and-aft direction while protecting the wheel bearings from damage has been a continuing problem.